Method and apparatus for determining whether to use buffer status report enhancement in a wireless communication system

Abstract

A method and apparatus are disclosed. In an example from the perspective of a User Equipment (UE), the UE receives a configuration, of a logical channel, associated with 2-step Random Access (RA) procedure. The UE triggers a Regular Buffer Status Report (BSR) for the logical channel. The UE determines whether to initiate a first 2-step RA procedure or to initiate a first 4-step RA procedure based on the configuration of the logical channel.

1 . A method of a User Equipment (UE), the method comprising:
 receiving a configuration, of a logical channel, associated with 2-step Random Access (RA) procedure;   triggering a Regular Buffer Status Report (BSR) for the logical channel; and   determining whether to initiate a first 2-step RA procedure or to initiate a first 4-step RA procedure based on the configuration of the logical channel.   
     
     
         2 . The method of  claim 1 , wherein:
 the UE initiates the first 2-step RA procedure for transmitting the Regular BSR based on the configuration indicating that the logical channel can trigger a 2-step RA procedure.   
     
     
         3 . The method of  claim 1 , wherein:
 the UE does not initiate the first 2-step RA procedure for transmitting the Regular BSR based on the configuration indicating that the logical channel cannot trigger a 2-step RA procedure.   
     
     
         4 . The method of  claim 1 , wherein:
 the UE initiates the first 4-step RA procedure for transmitting the Regular BSR based on the configuration indicating that the logical channel cannot trigger a 2-step RA procedure.   
     
     
         5 . The method of  claim 1 , wherein:
 a measured Reference Signal Received Power (RSRP) is higher than a configured RSRP threshold.   
     
     
         6 . The method of  claim 5 , comprising:
 initiating the first 2-step RA procedure for transmitting the Regular BSR based on the measured RSRP being higher than the configured RSRP threshold.   
     
     
         7 . The method of  claim 1 , wherein:
 triggering the Regular BSR is in response to uplink (UL) data for the logical channel becoming available.   
     
     
         8 . The method of  claim 1 , wherein:
 the UE does not have an available uplink (UL) resource for transmitting the Regular BSR.   
     
     
         9 . The method of  claim 1 , wherein:
 the UE does not have a valid Physical Uplink Control Channel (PUCCH) resource for a Scheduling Request (SR).   
     
     
         10 . The method of  claim 1 , wherein:
 the UE has a valid Physical Uplink Control Channel (PUCCH) resource for a Scheduling Request (SR).   
     
     
         11 . The method of  claim 1 , wherein:
 the UE is at least one of in or connected to a cell of a Non-Terrestrial Network (NTN).   
     
     
         12 . A User Equipment (UE), comprising:
 a control circuit;   a processor installed in the control circuit; and   a memory installed in the control circuit and operatively coupled to the processor, wherein the processor is configured to execute a program code stored in the memory to perform operations, the operations comprising:
 receiving a configuration, of a logical channel, associated with 2-step Random Access (RA) procedure; 
 triggering a Regular Buffer Status Report (BSR) for the logical channel; and 
 determining whether or not to initiate a first 2-step RA procedure based on the configuration of the logical channel. 
   
     
     
         13 . The UE of  claim 12 , wherein:
 the UE initiates the first 2-step RA procedure for transmitting the Regular BSR based on the configuration indicating that the logical channel can trigger a 2-step RA procedure.   
     
     
         14 . The UE of  claim 12 , wherein:
 the UE does not initiate the first 2-step RA procedure for transmitting the Regular BSR based on the configuration indicating that the logical channel cannot trigger a 2-step RA procedure.   
     
     
         15 . The UE of  claim 14 , wherein:
 the UE initiates a 4-step RA procedure for transmitting the Regular BSR based on the configuration indicating that the logical channel cannot trigger a 2-step RA procedure.   
     
     
         16 . The UE of  claim 12 , wherein:
 a measured Reference Signal Received Power (RSRP) is higher than a configured RSRP threshold.   
     
     
         17 . The UE of  claim 15 , the operations comprising:
 initiating the first 2-step RA procedure for transmitting the Regular BSR based on the measured RSRP being higher than the configured RSRP threshold.   
     
     
         18 . The UE of  claim 12 , wherein:
 triggering the Regular BSR is in response to uplink (UL) data for the logical channel becoming available.   
     
     
         19 . The UE of  claim 12 , wherein:
 the UE is at least one of in or connected to a cell of a Non-Terrestrial Network (NTN).   
     
     
         20 . A non-transitory computer-readable medium comprising processor-executable instructions that when executed by a User Equipment (UE) cause performance of operations, the operations comprising:
 receiving a configuration, of a logical channel, associated with 2-step Random Access (RA) procedure;   triggering a Regular Buffer Status Report (BSR) for the logical channel; and   determining whether to initiate a first 2-step RA procedure or to initiate a first 4-step RA procedure based on the configuration of the logical channel.